JP5696520B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

In recent years, so-called xerographic image forming apparatuses having charging means, exposure means, developing means, transfer means, fixing means, and the like have been further increased in speed and life due to technological progress of each member and system. Yes.
For example, an electrophotographic photosensitive member (referred to as “photosensitive member” where appropriate) used for image writing is used to suppress scratches and abrasion due to electrical and mechanical external forces such as charging means, developing means, transfer means, and cleaning means. By using a resin having a high mechanical strength as a material constituting the surface layer, a long life is achieved.

Patent Document 1 discloses a photoreceptor using an epoxy resin as a binder resin.
Patent Document 2 discloses using an epoxy resin and a charge transport material having an epoxy group.
Patent Documents 3 and 4 disclose that a charge transport material having a phenol resin and a hydroxyl group is used for the protective layer.

Further, in order to improve the cleaning property for removing the toner remaining on the surface of the photoreceptor, studies have been made to improve the characteristics of the surface layer.
For example, Patent Document 5 discloses a method of reducing the surface energy of the surface layer of the photoreceptor by dispersing fluorine-based resin particles in the surface layer of the photoreceptor.
Further, Patent Document 6 proposes to disperse fluorine resin particles in a protective layer obtained by polymerizing a compound having an unsaturated polymerizable functional group on the surface of the photoreceptor for further enhancement of durability. ing.

JP-A-56-51749 JP-A-8-278645 JP 2002-82469 A JP 2003-186234 A JP-A-63-221355 JP 2005-91500 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which wear resistance is maintained and generation of image flow is suppressed even when used repeatedly.

The invention according to claim 1 includes an electrophotographic photoreceptor in which the outermost surface layer includes fluorine-based resin particles and a fluorinated alkyl group-containing copolymer, and satisfies the following formula (1):
Charging means for charging the electrophotographic photoreceptor;
A latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
Cleaning means for removing the developer remaining on the surface of the electrophotographic photosensitive member;
Bei to give a,
The outermost surface layer of the electrophotographic photoreceptor is
At least one selected from guanamine compounds and melamine compounds;
At least one selected from a crosslinkable charge transport material having an alkoxy group and a structure derived from a crosslinkable charge transport material having an alkoxy group;
Further including
The total content of the guanamine compound and the melamine compound with respect to the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer is 0.1% by mass or more and 20% by mass or less. Yes,
Derived from the crosslinkable charge transport material having the alkoxy group and the crosslinkable charge transport material having the alkoxy group, based on the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer. An image forming apparatus having a total content of 10% to 40% by mass .
10 ≦ A × B ≦ 50 (1)
A: Total content [% by mass] of fluorine-based resin particles and fluorinated alkyl group-containing copolymer contained in the outermost surface layer
B: Abrasion amount of outermost layer when the electrophotographic photosensitive member is rotated 1000 [nm]
The invention according to claim 2 is the image formation according to claim 1, wherein the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer in the outermost surface layer of the electrophotographic photosensitive member is 21% by mass or less. apparatus.
Invention, the outermost surface layer of the electrophotographic photosensitive member, a crosslinkable charge transporting material having a water group, and at least one member selected from the structure derived from the crosslinkable charge transporting material having a hydroxyl group according to claim 3 further image forming apparatus according to including請 Motomeko 1 or claim 2.
The invention according to claim 4 is characterized in that the fluororesin particles contain at least one selected from a polymer of tetrafluoroethylene and a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene. Item 4. The image forming apparatus according to any one of Items 3 to 3.
The invention according to claim 5 is characterized in that the fluorinated alkyl group-containing copolymer is a fluorinated alkyl group-containing copolymer containing repeating units represented by the following structural formula A and the following structural formula B. The image forming apparatus according to any one of claims 1 to 4.

(In Structural Formula A and Structural Formula B, l, m and n are integers of 1 or more, p, q, r and s are 0 or an integer of 1 or more, t is an integer of 1 or more and 7 or less, R ¹ , R ² , R ³ and R ⁴ are a hydrogen atom or an alkyl group, X is an alkylene chain, halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond, Y is an alkylene chain, halogen-substituted Represents an alkylene chain, — (C _z H _2z-1 (OH)) — or a single bond, _z represents an integer of 1 or more, and Q represents —O— or —NH—.
The invention according to claim 6 is the image according to any one of claims 1 to 5, wherein the charging means is means for charging the electrophotographic photosensitive member without contacting the electrophotographic photosensitive member. Forming equipment.
The invention according to claim 7 is the image forming apparatus according to any one of claims 1 to 6, wherein the moving speed of the outer peripheral surface of the electrophotographic photosensitive member is 500 mm / s or more.

According to the first aspect of the present invention, the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer contained in the outermost surface layer of the electrophotographic photosensitive member and the wear amount of the outermost surface layer are expressed by the above formula ( As compared with the case where the relationship of 1) is not satisfied , and the case where the type and content of the charge transporting material contained in the outermost surface layer of the electrophotographic photosensitive member are not taken into consideration , the abrasion resistance of the photosensitive member even when used repeatedly. Is maintained, and an image forming apparatus that suppresses the occurrence of image flow is provided.
According to the second aspect of the present invention, compared to the case where the total content of the fluorine-based resin particles and the fluorinated alkyl group-containing copolymer in the outermost surface layer of the electrophotographic photosensitive member exceeds 21% by mass, the image flow is generated. There is provided an image forming apparatus in which the image is suppressed.
According to the invention of claim 3, in comparison with the case without consideration of the type of charge transporting material contained in the outermost layer of the electrophotographic photosensitive member, repeatedly it is used in the wear resistance of the photosensitive member Is maintained, and an image forming apparatus that suppresses the occurrence of image flow is provided.
According to the invention of claim 4, when the fluorine resin particles do not contain at least one selected from a polymer of tetrafluoroethylene and a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene. In comparison, it is possible to provide an image forming apparatus that maintains abrasion resistance and suppresses the occurrence of image flow.
According to the invention of claim 5, the fluorinated alkyl group-containing copolymer contained in the outermost surface layer of the electrophotographic photosensitive member includes a fluorinated unit containing the repeating unit represented by the structural formula A and the structural formula B. As compared with a case where the copolymer is not an alkyl group-containing copolymer, there is provided an image forming apparatus in which abrasion resistance is maintained and image generation is suppressed.
According to the sixth aspect of the present invention, wear resistance is maintained and image flow is maintained as compared with the case where the charging unit is a unit that contacts the electrophotographic photosensitive member and charges the electrophotographic photosensitive member. There is provided an image forming apparatus in which the occurrence of the above is suppressed.
According to the seventh aspect of the present invention, even when the moving speed of the outer peripheral surface of the electrophotographic photosensitive member is as high as 500 mm / s or more, the occurrence of image flow is suppressed as compared with the case where Expression (1) is not satisfied. An image forming apparatus capable of obtaining a high-productivity image is provided.

1 is a schematic cross-sectional view illustrating an example of an electrophotographic photosensitive member used in the present embodiment. It is a schematic cross section which shows the other example of the electrophotographic photosensitive member used by this embodiment. It is a schematic cross section which shows the other example of the electrophotographic photosensitive member used by this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the cleaning blade with which the cleaning apparatus used by this embodiment is provided. It is a schematic block diagram which shows the other example of the image forming apparatus of this embodiment. It is a figure which shows the evaluation criteria of resolution evaluation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.
In the image forming apparatus according to this embodiment, the outermost surface layer includes fluororesin particles and a fluorinated alkyl group-containing copolymer, and satisfies the following formula (1), and the electrophotographic photoreceptor is charged. A charging means, a latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member, and a developer containing toner on the electrostatic latent image formed on the surface of the electrophotographic photosensitive member Developing means for forming a toner image by developing, a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member to a recording medium, and a developer remaining on the surface of the electrophotographic photosensitive member are removed. Cleaning means.
10 ≦ A × B ≦ 50 (1)
A: Total content [% by mass] of fluorine-based resin particles and fluorinated alkyl group-containing copolymer contained in the outermost surface layer
B: Abrasion amount of outermost layer when the electrophotographic photosensitive member is rotated 1000 [nm]

The present inventors have suppressed the image flow if the wear amount is relatively large even if the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer contained in the outermost surface layer of the electrophotographic photoreceptor is small. The present inventors have found that even if the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer is large, the image flow is suppressed if the wear amount is small. In the image forming apparatus according to the present embodiment, as described above, the total content (% by mass) of the fluororesin particles and the fluorinated alkyl group-containing copolymer contained in the outermost surface layer of the electrophotographic photosensitive member, When the wear amount (nm) of the outermost surface layer satisfies the relationship of the above formula (1), the wear resistance of the photoreceptor is maintained and the occurrence of image flow is suppressed. Details are unknown, but when the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer contained in the outermost surface layer of the photoconductor and the wear amount of the outermost surface layer satisfy the above (1) The balance between the removal of deposits such as discharge products that cause image quality abnormalities such as image flow and the wear resistance is balanced, and the wear resistance of the photoconductor is maintained even after repeated image formation. It is estimated that the occurrence is suppressed.
From the viewpoint of maintaining wear resistance and suppressing the occurrence of image flow, it is preferably 12 ≦ A × B ≦ 42, and more preferably 15 ≦ A × B ≦ 30.

[Electrophotographic photoreceptor]
First, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings.
FIG. 1 schematically shows an example of the configuration of the electrophotographic photoreceptor according to the present embodiment, and FIGS. 2 and 3 schematically show other configurations of the electrophotographic photoreceptor, respectively.
An electrophotographic photoreceptor 7A shown in FIG. 1 is a so-called function-separated photoreceptor (or laminated photoreceptor), and an undercoat layer 1 is provided on a conductive substrate 4, on which a charge generation layer 2 and a charge are formed. A photosensitive layer constituted by sequentially forming the transport layer 3 is provided, and a surface protective layer 5 is provided thereon as an outermost surface layer.

The electrophotographic photoreceptor 7B shown in FIG. 2 is a function-separated photoreceptor in which the functions are separated into the charge generation layer 2 and the charge transport layer 3 in the same manner as the electrophotographic photoreceptor 7B shown in FIG. A structure in which an undercoat layer 1 is provided on a conductive substrate 4, a photosensitive layer 6 </ b> B in which a charge transport layer 3 and a charge generation layer 2 are sequentially formed, and a surface protective layer 5 is provided thereon. It is what you have.
An electrophotographic photoreceptor 7C shown in FIG. 3 is a function-integrated photoreceptor including a charge generation material and a charge transport material in the same layer (charge generation / charge transport layer 6). The layer 1 is provided, and the charge generation / charge transport layer 6 and the surface protective layer 5 are sequentially formed thereon. In the electrophotographic photoreceptor 7C, a single-layer type photosensitive layer composed of the charge generation / charge transport layer 6 is formed.
In the electrophotographic photoreceptor shown in FIGS. 1 to 3, the undercoat layer 1 may or may not be provided. Further, an intermediate layer may be provided between the undercoat layer 1 and the photosensitive layer. Further, the photosensitive layer may be the outermost surface layer without providing the surface protective layer.
Hereinafter, each element will be described based on the electrophotographic photosensitive member 7A shown in FIG. 1 as a representative example.

<Surface protective layer>
The surface protective layer 5 is the outermost surface layer in the electrophotographic photoreceptor 7 </ b> A, and is a layer provided to protect the photosensitive layer composed of the charge generation layer 2 and the charge transport layer 3. The surface protective layer 5 according to this embodiment includes at least fluorine-based resin particles and a fluorinated alkyl group-containing copolymer. By having such a surface protective layer 5, the surface of the photoreceptor 7 </ b> A is given resistance to abrasion, scratches, and the like, and toner transfer efficiency is improved.

-Fluorine resin particles-
When the surface protective layer 5 contains fluorine-based resin particles, the frictional force with a contact member such as a cleaning blade for removing toner remaining on the surface of the photoreceptor after the toner image is transferred is reduced. Wear on the surface of the electrophotographic photosensitive member is effectively suppressed. On the other hand, it is considered that the frictional force between the residual toner and the cleaning blade is maintained, and foreign matters such as residual toner are easily removed.

  The fluororesin particles contained in the surface protective layer 5 are not particularly limited, but include tetrafluoroethylene resin (PTFE), trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, It is desirable to select one type or two or more types from vinylidene fluoride resin, difluorodiethylene chloride resin, and copolymers thereof. From the viewpoint of wear resistance, a polymer of fluoroethylene and 4-fluoroethylene are preferable. It is further desirable to include at least one selected from a copolymer of ethylene fluoride and perfluoroalkoxyethylene.

The average primary particle size of the fluororesin particles is desirably 0.05 μm or more and 1 μm or less, and more desirably 0.1 μm or more and 0.5 μm or less.
The average primary particle size of the fluororesin particles was measured by diluting with the same solvent as the dispersion in which the fluororesin particles were dispersed, using a laser diffraction particle size distribution analyzer LA-920 (manufactured by Horiba). This is a value obtained by measuring the liquid at a refractive index of 1.35.

  The content of the fluororesin particles with respect to the total solid content of the surface protective layer 5 is preferably 1% by mass or more and 40% by mass or less, and more preferably 3% by mass or more and 20% by mass or less.

-Fluorinated alkyl group-containing copolymer-
When the surface protective layer 5 contains a fluorinated alkyl group-containing copolymer, the dispersion stability of the fluororesin particles is maintained.
Although it does not specifically limit as a fluorinated alkyl group containing copolymer contained in the surface protective layer 5, The fluorinated alkyl containing the repeating unit represented by following Structural formula (A) and Structural formula (B) It is desirable to be a group-containing copolymer, for example, by graft polymerization using a macromonomer composed of an acrylic ester compound, a methacrylic ester compound, etc., and perfluoroalkylethyl (meth) acrylate and perfluoroalkyl (meth) acrylate. It is more desirable that the resin be synthesized. Here, (meth) acrylate represents acrylate or methacrylate.

In Structural Formula A and Structural Formula B, l, m, and n are integers of 1 or more, p, q, r, and s are 0 or an integer of 1 or more, t is an integer of 1 to 7, and R ¹ , R ² , R ³ and R ⁴ are a hydrogen atom or an alkyl group, X is an alkylene chain, halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond, Y is an alkylene chain, halogen-substituted alkylene _{chain, - (C z H 2z-} 1 (OH)) - or a single bond. z represents an integer of 1 or more. Q represents -O- or -NH-.

  The weight average molecular weight of the fluorinated alkyl group-containing copolymer is preferably from 10,000 to 100,000, and more preferably from 30,000 to 100,000.

  In the fluorinated alkyl group-containing copolymer, the content ratio of the structural formula (A) to the structural formula (B), that is, l: m is preferably 1: 9 to 9: 1, and more preferably 3: 7 to 7: 3. desirable.

In the structural formula (A) and the structural formula (B), examples of the alkyl group represented by R ¹ , R ² , R ^3, and R ⁴ include a methyl group, an ethyl group, and a propyl group. R ¹ , R ² , R ³ and R ⁴ are preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

  The fluorinated alkyl group-containing copolymer may further contain a repeating unit represented by the structural formula (C). The content of structural formula (C) is preferably 10: 0 to 7: 3 as l + m: z in terms of the sum of the contents of structural formula (A) and structural formula (B), ie, l + m, and 9: 1 7 to 3 is more desirable.

[In Structural Formula (C), R ⁵ and R ⁶ represent a hydrogen atom or an alkyl group, and z represents an integer of 1 or more. ]

R ⁵ and R ⁶ are preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a methyl group.

  The content of the fluorinated alkyl group-containing copolymer in the surface protective layer 5 is desirably 1% by mass or more and 10% by mass or less with respect to the mass of the fluororesin particles.

  Further, the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer in the surface protective layer 5 is desirably 40% by mass or less, and more desirably 21% by mass or less. When the total content is 40% by mass or less, there is a high possibility that an improvement in wear resistance can be achieved while minimizing a decrease in resolution. However, the total content of the fluororesin particles and the fluorinated alkyl group-containing copolymer is preferably 1% by mass or more and more preferably 3% by mass or more from the viewpoint of surely exhibiting the effect of improving wear resistance. .

The surface protective layer 5 includes a compound having a guanamine structure (hereinafter referred to as “guanamine compound” as appropriate) and a compound having a melamine structure (hereinafter referred to as appropriate), in addition to the fluororesin particles and the fluorinated alkyl group-containing copolymer. And at least one selected from “a melamine compound”), a crosslinkable charge transport material having an alkoxy group as a charge transport material, and a crosslinkable charge transport material having a hydroxyl group. desirable. The total content of the guanamine compound and the melamine compound is 0.1% by mass or more and 20% by mass or less based on the total solid content of the outermost surface layer excluding the fluorine resin particles and the fluorinated alkyl group-containing copolymer, The content of the crosslinkable charge transporting material having an alkoxy group with respect to the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer is 10% by mass or more and 40% by mass or less. desirable.
Since the surface protective layer 5 has the above-described configuration, the abrasion resistance and electrical stability of the electrophotographic photosensitive member are further improved, the occurrence of image flow is also suppressed, and good image quality can be repeatedly formed. High reliability and long life of the forming apparatus can be further improved.

-Guanamine compounds-
Here, the guanamine compound will be described. The guanamine compound used in the present embodiment is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.
The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). In addition, the compound shown by general formula (A) may be used individually by 1 type, and may use 2 or more types together. In particular, when two or more compounds represented by the general formula (A) are mixed and used as a multimer (oligomer) having the structural unit as a structural unit, the solubility in a solvent is improved.

In general formula (A), R ₁ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R _{2 to} R ₅ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ⁶ . R ₆ represents a linear or branched alkyl group having 1 to 10 carbon atoms.
In the general formula (A), the alkyl group representing R ₁ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.
In general formula (A), the phenyl group represented by R ₁ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.
In general formula (A), the alicyclic hydrocarbon group representing R ₁ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.
In the general formula (A), in “—CH ₂ —O—R ₆ ” representing R _{2 to} R ₅ , the alkyl group representing R ₆ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 or less and 8 or more, and more preferably 1 or more and 6 or less. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.
As the compound represented by the general formula (A), it is particularly desirable that R ₁ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R _{2 to} R ₅ are each independently —CH ₂ —O. It is a compound represented by —R ₆ . R ₆ is preferably selected from a methyl group and an n-butyl group.
The compound represented by the general formula (A) is synthesized by, for example, a known method using guanamine and formaldehyde (for example, Experimental Chemistry Course 4th Edition, Volume 28, page 430).
Specific examples of the compound represented by the general formula (A) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

Commercially available products of the compound represented by the general formula (A) include, for example, “Superbecamine (R) L-148-55, Superbecamine (R) 13-535, Superbecamine (R) L-145- 60, Superbecamine (R) TD-126 "manufactured by Dainippon Ink Co., Ltd.," Nicarac BL-60, Nicarac BX-4000 "manufactured by Nippon Carbide, and the like.
In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

-Melamine compounds-
Next, the melamine compound will be described. The melamine compound used in the present embodiment is a compound having a melamine skeleton (structure), and is particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit, and the degree of polymerization is, for example, 2 or more and 200 or less (desirably 2 or more and 100 or less). In addition, the compound shown by General formula (B) or its multimer may be used individually by 1 type, and may use 2 or more types together. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer. In particular, when the compound represented by the general formula (B) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the same as a structural unit, the solubility in a solvent is improved.

In general formula (B), R ^{6 to} R ¹¹ each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹² , and R ¹² is branched from 1 to 5 carbon atoms. Or a good alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.
The compound represented by the general formula (B) is synthesized by a known method using, for example, melamine and formaldehyde (for example, synthesized in the same manner as the melamine resin in Experimental Chemistry Course 4th edition, Volume 28, page 430). Is done.
Specific examples of the compound represented by the general formula (B) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (Nippon Yushi Co., Ltd.), Super Becamine (R) TD-139-60 (Dainippon Ink Co., Ltd.), Uban 2020 (Mitsui Chemicals), Smitex Resin M-3 (Sumitomo Chemical Co., Ltd.), Nicarac MW-30 (Made by Nippon Carbide).
In addition, the compound represented by the general formula (B) (including multimers) can be used in an appropriate solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

-Charge transport material-
Next, the charge transport material will be described. Examples of the charge transport material contained in the surface protective layer include those having at least one substituent selected from a hydroxyl group, an alkoxy group, an amino group, a thiol group, and a carboxyl group. In particular, examples of the charge transporting material include those having at least two (or three) substituents selected from a hydroxyl group, an alkoxy group, an amino group, a thiol group, and a carboxyl group. As described above, the number of reactive functional groups (substituents) in the charge transporting material increases, so that the crosslink density increases and a cross-linked film having higher strength is obtained, and wear of the electrophotographic photosensitive member is suppressed.

The charge transporting material is preferably a compound represented by the following general formula (I).
_{F - ((- R 1 -X} ) n1 (R 2) n2 -Y) n3 (I)
In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, and n3 represents an integer of 1 or more and 4 or less. X represents an oxygen, NH, or sulfur atom, and Y represents a hydroxyl group, an alkoxy group, an amino group, a thiol group, and a carboxyl group.
In general formula (I), examples of the compound having a hole transporting ability in an organic group derived from a compound having a hole transporting ability indicating F include arylamine derivatives. Examples of arylamine derivatives include triphenylamine derivatives and tetraphenylbenzidine derivatives.
The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II). The compound represented by the general formula (II) is particularly excellent in charge mobility, stability against oxidation and the like.

In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or substituted or unsubstituted. D represents — (— R ₁ —X) _n1 (R ₂ ) _n2 —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 or less. R ₁ and R ₂ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, n2 represents 0 or 1, and X represents oxygen. , NH, or a sulfur atom, and Y represents a hydroxyl group, an alkoxy group, an amino group, a thiol group, or a carboxyl group.
In the general formula (II), “— (— R ₁ —X) _n1 (R ₂ ) _n2 —Y” representing D is the same as in the general formula (I), and R ₁ and R ₂ are each independently carbon. A linear or branched alkylene group having a number of 1 or more and 5 or less. N1 is preferably 1. N2 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group.
The total number of D in the general formula (II) corresponds to n3 in the general formula (I), preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less. That is, in the general formula (I) or the general formula (II), when the total number of D is preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less in one molecule, the crosslinking density is increased and the strength is higher. A cross-linked film is obtained, and in particular, the rotational torque of the electrophotographic photosensitive member when using a cleaning blade is reduced, so that damage to the blade and wear of the electrophotographic photosensitive member are suppressed. Details of this are unknown, but by increasing the number of reactive functional groups, a cured film with a high crosslink density can be obtained, and molecular motion on the extreme surface of the electrophotographic photoreceptor is suppressed, allowing mutual interaction with the blade member surface molecules. It is presumed that the action is weakened.
In general formula (II), Ar ^{1 to} Ar ⁴ are preferably any of the following formulas (1) to (7). In addition, the following formulas (1) to (7) collectively indicate “— (D) _C1 ” to “— (D) _C4 ” that can be connected to each of Ar ^{1 to} Ar ^4. _C ".

In formulas (1) to (7), R ⁹ is a phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ^{10 to} R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a carbon number, respectively. One selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom Ar represents a substituted or unsubstituted arylene group, D and c are the same as “D” and “c” in formula (II), s represents 0 or 1, and t is 1 or more, respectively. Integer less than 3 Represent.
Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

In formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. This represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.
In addition, Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

In formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. This represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent 1 Represents an integer of 10 or less, and t represents an integer of 1 or more and 3 or less, respectively.
W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing a predetermined hydrogen atom from the aryl groups of (1) to (7).
Specific examples of the compound represented by the general formula (I) include compounds I-1 to I-34 shown below. In addition, the compound shown by the said general formula (I) is not limited at all by these.

  In the present embodiment, the surface protective layer of the photoconductor includes a crosslinkable charge transport material having an alkoxy group and a crosslinkable charge transport having a hydroxyl group as charge transport materials from the viewpoint of wear resistance, image quality characteristics, electrical characteristics, and the like. It is desirable to contain a substance. Hereinafter, the crosslinkable charge transport material having an alkoxy group and the crosslinkable charge transport material having a hydroxyl group may be collectively referred to as a “specific charge transport material”.

The total content of the guanamine compound and the melamine compound in the surface protective layer 5 is 0.1% by mass or more based on the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer. The content of the crosslinkable charge transport material having an alkoxy group with respect to the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer is 10% by mass or more and 40% by mass or less. It is desirable that it is less than mass%.
If the total content of the guanamine compound (for example, the compound represented by the general formula (A)) and the melamine compound (for example, the compound represented by the general formula (B)) is within the above range, Compared to the case where the film is denser and the wear resistance is improved, the electric characteristics and the ghost resistance are improved.
In addition, when the content of the crosslinkable charge transport material having an alkoxy group is within the above range, a decrease in electrical characteristics is suppressed as compared with a case where the content is less than the above range, and electrical or mechanical is applied from the outside of the photoreceptor. When the stress is applied to the photoconductor, the tolerance is further increased.

  The total content of the charge transporting material and the total content of the guanamine compound and the melamine compound in the surface protective layer 5 are the solid content concentrations of these compounds in the coating solution for forming the surface protective layer. Is controlled by adjusting.

-Other ingredients-
The surface protective layer 5 includes at least one selected from a guanamine compound (for example, a compound represented by the general formula (A)) and a melamine compound (for example, a compound represented by the general formula (B)), and the charge transporting material. A phenol resin, a melamine resin, a urea resin, an alkyd resin, or the like may be mixed and used together with a cross-linked product (for example, a compound represented by the general formula (I)). Further, in order to improve the strength, a compound having more functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) is used as the material in the crosslinked product. Copolymerization is also effective.

The surface protective layer 5 is mixed with other thermosetting resins such as phenol resin, melamine resin, and benzoguanamine resin for the purpose of effectively suppressing oxidation by the discharge generated gas so that the discharge generated gas is not excessively adsorbed. May be.
Further, it is desirable to add a surfactant to the surface protective layer 5, and the surfactant to be used is not particularly limited as long as it is a surfactant containing at least one of a fluorine atom, an alkylene oxide structure, and a silicone structure. However, those having a plurality of the above structures have high affinity and compatibility with the charge transporting organic compound, improve the film forming property of the coating solution for forming the surface protective layer, and suppress wrinkles and unevenness of the surface protective layer 5 Is done.

  Various things are mentioned as surfactant which has a fluorine atom. Specific examples of the surfactant having a fluorine atom and an acrylic structure include Polyflow KL600 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF-351, EF-352, EF-801, EF-802, EF-601 (above, JEMCO Etc.). The surfactant having an acrylic structure mainly includes those obtained by polymerizing or copolymerizing monomers such as acrylic or methacrylic compounds.

  Examples of the surfactant having a fluorine atom include surfactants having a perfluoroalkyl group, and more specifically, perfluoroalkylsulfonic acids (for example, perfluorobutanesulfonic acid, perfluorooctane). Sulfonic acid, etc.), perfluoroalkyl carboxylic acids (for example, perfluorobutane carboxylic acid, perfluorooctane carboxylic acid, etc.), and perfluoroalkyl group-containing phosphate esters. Perfluoroalkylsulfonic acids and perfluoroalkylcarboxylic acids may be salts thereof and amide-modified products thereof.

Examples of commercially available perfluoroalkyl sulfonic acids include Megafac F-114 (manufactured by Dainippon Ink & Chemicals, Inc.), F-top EF-101, EF102, EF-103, EF-104, EF-105, and EF-. 112, EF-121, EF-122A, EF-122B, EF-122C, EF-123A (manufactured by JEMCO), AK, 501 (manufactured by Neos) and the like.
Examples of commercially available perfluoroalkyl carboxylic acids include Megafac F-410 (manufactured by Dainippon Ink & Chemicals, Inc.), Ftop EF-201, EF-204 (and above, manufactured by JEMCO).
As commercial products of perfluoroalkyl group-containing phosphates, MegaFac F-493, F-494 (above, manufactured by Dainippon Ink & Chemicals, Inc.) F-top EF-123A, EF-123B, EF-125M, EF -132 (above, manufactured by JEMCO).

Examples of the surfactant having an alkylene oxide structure include polyethylene glycol, polyether antifoaming agent, and polyether-modified silicone oil.
The polyethylene glycol preferably has a number average molecular weight of 2000 or less, and the polyethylene glycol having a number average molecular weight of 2000 or less includes polyethylene glycol 2000 (number average molecular weight 2000), polyethylene glycol 600 (number average molecular weight 600), polyethylene glycol 400. (Number average molecular weight 400), polyethylene glycol 200 (number average molecular weight 200) and the like.
Moreover, as a polyether antifoamer, PE-M, PE-L (above, Wako Pure Chemical Industries Ltd. make), antifoamer No. 1. Antifoaming agent No. 1 5 (above, manufactured by Kao Corporation).

  Examples of the surfactant having a silicone structure include general silicone oils such as dimethyl silicone, methylphenyl silicone, diphenyl silicone and derivatives thereof.

  Furthermore, surfactants having both a fluorine atom and an alkylene oxide structure include those having an alkylene oxide structure or a polyalkylene structure in the side chain, and the end of the alkylene oxide or polyalkylene oxide structure is substituted with a fluorine-containing substituent. Etc. Specific examples of the surfactant having an alkylene oxide structure include, for example, Megafac F-443, F-444, F-445, and F-446 (above, Dainippon Ink & Chemicals, Inc.), POLY FOX PF636. , PF6320, PF6520, PF656 (above, manufactured by Kitamura Chemical Co., Ltd.).

  As surfactants having both an alkylene oxide structure and a silicone structure, KF351 (A), KF352 (A), KF353 (A), KF354 (A), KF355 (A), KF615 (A), KF618, KF945 (A), KF6004 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), TSF4440, TSF4445, TSF4450, TSF4446, TSF4452, TSF4453, TSF4460 (above, manufactured by GE Toshiba Silicon), BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 341, 344, 345, 346, 347, 348, 370, 375, 377, 378, UV3500, UV3510, UV3570, etc. (above, Big Chemie Ja Emissions Co., Ltd.) and the like.

The content of the surfactant is desirably 0.01% by mass or more and 1% by mass or less with respect to the solid content when the fluororesin particles of the surface protective layer 5 or the fluorinated alkyl group-containing copolymer is excluded. More preferably, it is 0.02 mass% or more and 0.5 mass% or less. When the content of the surfactant having a fluorine atom is 0.01% by mass or more, the effect of preventing coating film defects such as suppression of wrinkles and unevenness tends to increase. Moreover, it becomes difficult to isolate | separate the surfactant and fluorine resin which have the said fluorine atom, and the intensity | strength of the hardened | cured material obtained by the content of the surfactant which has a fluorine atom being 1 mass% or less tends to be maintained. It is in.
The surface protective layer 5 may be further mixed with other coupling agents and fluorine compounds for the purpose of adjusting the film formability, flexibility, lubricity, and adhesion. Various silane coupling agents and commercially available silicone hard coat agents are used.

  As the silane coupling agent, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, and the like are used. As a commercially available hard coat agent, KP-85, X-40-9740, X-8239 (manufactured by Shin-Etsu Silicone), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning) Etc. are used.

  In order to impart water repellency and the like, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) Fluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyl Fluorine-containing compounds such as triethoxysilane may be added. Although the silane coupling agent is used in an arbitrary amount, the amount of the fluorine-containing compound may be 0.25 times or less by mass with respect to the compound containing no fluorine from the viewpoint of the film formability of the crosslinked film. desirable.

Further, a resin that dissolves in alcohol may be added for the purpose of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like of the surface protective layer 5.
Here, the resin that dissolves in alcohol means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. Examples of resins that can be dissolved in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral has been modified with formal, acetoacetal, etc. B, K, etc.), polyamide resin, cellulose resin, polyvinylphenol resin and the like. In particular, polyvinyl acetal resin and polyvinyl phenol resin are desirable in terms of electrical characteristics.
The resin preferably has a weight average molecular weight of 2,000 to 100,000, and more preferably 5,000 to 50,000. If the molecular weight of the resin is less than 2,000, the effect due to the addition of the resin tends to be insufficient, and if it exceeds 100,000, the solubility decreases and the addition amount is limited. It tends to cause defects.
Further, the addition amount of the resin is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less when the fluororesin particles or the fluorinated alkyl group-containing copolymer is excluded. 5 mass% or more and 20 mass% or less are more desirable. If the addition amount of the resin is less than 1% by mass, the effect of the addition of the resin tends to be insufficient. Image blur is likely to occur.

It is desirable to add an antioxidant to the surface protective layer 5 for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated in the charging device. When the mechanical strength of the surface of the photoconductor is increased and the photoconductor has a long life, the photoconductor is in contact with an oxidizing gas for a long time, and thus oxidation resistance is required. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used.
The addition amount of the antioxidant is preferably 20% by mass or less and more preferably 10% by mass or less when the fluororesin particles and the fluorinated alkyl group-containing copolymer are excluded.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

Commercially available hindered phenol antioxidants include “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox 1330”, “Irganox 3114”. , “Irganox 1076” (manufactured by Ciba Japan), “3,5-di-t-butyl-4-hydroxybiphenyl”, and the like.
As the hindered amine-based antioxidant, “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744” (manufactured by Sankyo Lifetech), “Tinuvin 144”, “Tinuvin 622LD” (above, Ciba Japan)), “Mark LA57”, “Mark LA67”, “Mark LA62”, “Mark LA68”, “Mark LA63” (above, manufactured by Adeka), and “Smilizer-TPS”, “Smilizer” as thioethers. TP-D "(manufactured by Sumitomo Chemical Co., Ltd.), and the phosphite system is" Mark 2112 "," Mark PEP-8 "," Mark PEP-24G "," Mark PEP-36 "," Mark 329K " , “Mark HP-10” (manufactured by Adeka) and the like.

Furthermore, various particles may be added to the surface protective layer 5 for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles.
The colloidal silica used as the silicon-containing particles is obtained by dispersing silica having an average particle diameter of 1 nm or more and 100 nm or less, desirably 10 nm or more and 30 nm or less in an organic solvent such as an acidic or alkaline aqueous dispersion, alcohol, ketone, or ester. You may use what was chosen from the thing and generally marketed.
The solid content of colloidal silica in the surface protective layer 5 is not particularly limited, but from the viewpoint of film forming properties, electrical characteristics, and strength, the fluorine-based resin particles or alkyl fluoride of the surface protective layer 5 Based on the solid content when the group-containing copolymer is removed, it is used in the range of 0.1 to 50% by mass, preferably 0.1 to 30% by mass.

The silicone particles used as the silicon-containing particles are selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles, and those commercially available are generally used. These silicone particles are spherical, and the average particle size is desirably 1 nm or more and 500 nm or less, and more desirably 10 nm or more and 100 nm or less. Silicone particles are small particles that are chemically inert and excellent in dispersibility in resins, and since the content required to obtain more sufficient properties is low, the crosslinking reaction is not hindered. The surface properties of the photographic photoreceptor are improved. In other words, the surface of the electrophotographic photosensitive member is improved in lubricity and water repellency in a state where variations are incorporated into a strong cross-linked structure, and good wear resistance and adherence to contaminants are maintained over a long period of time. The
The content of the silicone particles in the protective layer 5 is preferably 0.1% by mass or more and 30% based on the solid content when the fluororesin particles or the fluorinated alkyl group-containing copolymer in the protective layer 5 is excluded. It is 0.5 mass% or less, More desirably, it is 0.5 mass% or more and 10 mass% or less.

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and “8th Polymer Material Forum Lecture Proceedings p89”. As shown, particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO ₂ —TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO. For the same purpose, an oil such as silicone oil may be added. Silicone oils include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane; amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, mercapto-modified poly Reactive silicone oils such as siloxane and phenol-modified polysiloxane; cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane; 1,3,5- Trimethyl-1.3.5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclo Cyclic methylphenylcyclosiloxanes such as trasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane; cyclic phenylcyclosiloxanes such as hexaphenylcyclotrisiloxane Fluorine-containing cyclosiloxanes such as (3,3,3-trifluoropropyl) methylcyclotrisiloxane; hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixtures, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane; penta And vinyl group-containing cyclosiloxanes such as vinylpentamethylcyclopentasiloxane.

In addition, conductive particles such as metal, metal oxide, and carbon black may be added to the surface protective layer 5. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. . These may be used alone or in combination of two or more. When using 2 or more types in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.
The average particle diameter of the conductive particles is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of the transparency of the protective layer.

  The surface protective layer 5 is provided with a curing catalyst for accelerating the curing of the guanamine compound (for example, the compound represented by the general formula (A)), the melamine compound (for example, the compound represented by the general formula (B)) and the charge transport material. May be used. An acid catalyst is preferably used as the curing catalyst. Acid-based catalysts include acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, lactic acid and other aliphatic carboxylic acids, benzoic acid, phthalic acid, terephthalic acid, trimellitic acid, etc. Aromatic carboxylic acids, methane sulfonic acids, dodecyl sulfonic acids, benzene sulfonic acids, aliphatics such as dodecyl benzene sulfonic acids, naphthalene sulfonic acids, and aromatic sulfonic acids are used, but sulfur-containing materials should be used. desirable.

By using a sulfur-containing material as a curing catalyst, the sulfur-containing material can be converted into a guanamine compound (for example, a compound represented by the general formula (A)) and a melamine compound (for example, a compound represented by the general formula (B)) or charge transport. The mechanical strength of the surface protective layer 5 obtained by exhibiting an excellent function as a curing catalyst for the material and promoting the curing reaction is further improved.
Furthermore, when the compound represented by the general formula (I) (including the general formula (II)) is used as the charge transport material, the sulfur-containing material exhibits an excellent function as a dopant for these charge transport materials. In addition, the electrical characteristics of the obtained functional layer are further improved. As a result, when an electrophotographic photosensitive member is formed, all of mechanical strength, film formability, and electrical characteristics are achieved at a high level.

  The sulfur-containing material as the curing catalyst is desirably normal temperature (for example, 25 ° C.) or one that exhibits acidity after heating, and at least one of organic sulfonic acid and derivatives thereof is particularly preferable from the viewpoint of adhesiveness, ghost, and electrical characteristics. desirable. The presence of these catalysts in the protective layer 5 is easily confirmed by XPS or the like.

Examples of the organic sulfonic acid and / or a derivative thereof include p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid. Among these, paratoluenesulfonic acid and dodecylbenzenesulfonic acid are desirable from the viewpoint of catalytic ability and film formability. Further, an organic sulfonate may be used as long as it is dissociated to some extent in the curable resin composition.
In addition, by using a so-called thermal latent catalyst that increases the catalytic ability when a temperature above a certain level is applied, the catalytic ability is low at the liquid storage temperature and the catalytic ability is high at the time of curing. And storage stability.

As a heat latent catalyst, for example, a microcapsule in which an organic sulfone compound or the like is encapsulated in a polymer form, an adsorbed acid or the like on a pore compound such as zeolite, and a proton acid and / or proton acid derivative is blocked with a base Thermal latent proton acid catalyst, proton acid and / or proton acid derivative esterified with primary or secondary alcohol, proton acid and / or proton acid derivative blocked with vinyl ethers and / or vinyl thioethers And boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.
Among them, a product obtained by blocking a protonic acid and / or a protonic acid derivative with a base in terms of catalytic ability, storage stability, availability, and cost is desirable.

  As the protonic acid of the heat latent protonic acid catalyst, sulfuric acid, hydrochloric acid, acetic acid, formic acid, nitric acid, phosphoric acid, sulfonic acid, monocarboxylic acid, polycarboxylic acids, propionic acid, oxalic acid, benzoic acid, acrylic acid, methacrylic acid, Itaconic acid, phthalic acid, maleic acid, benzenesulfonic acid, o, m, p-toluenesulfonic acid, styrenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, Examples include tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, dodecylbenzenesulfonic acid and the like. In addition, as protonic acid derivatives, neutralized products such as alkali metal salts of alkaline acids or alkaline earth metal circles such as sulfonic acid and phosphoric acid, and polymer compounds in which a protonic acid skeleton is introduced into the polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines. Amines are classified as primary, secondary or tertiary amines. There is no restriction in particular and any of them may be used.

  Examples of the primary amine include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, hexylamine, 2-ethylhexylamine, secondary butylamine, allylamine, and methylhexylamine.

  As secondary amines, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-t-butylamine, dihexylamine, di (2-ethylhexyl) amine, N-isopropyl N-isobutylamine , Di (2-ethylhexyl) amine, disecondary butylamine, diallylamine, N-methylhexylamine, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, morpholine, N -Methylbenzylamine and the like.

  As tertiary amines, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-t-butylamine, trihexylamine, tri (2-ethylhexyl) amine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N-dimethylallylamine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N′-tetramethyl-1,3 -Diaminopropane, N, N, N ', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, N-propyldiallylamine, 3-dimethylaminopropanol, 2-ethylpyrazine, 2, 3-di Tilpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine, 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methyl Pyridine, 4- (5-nonyl) pyridine, imidazole, N-methylpiperazine and the like can be mentioned.

  Commercially available products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH 7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfonic acid dissociation, manufactured by King Industries, Inc. Isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.) “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE 2530” (P-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH 6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9.0, Dissociation temperature 107 ), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene glycol solvent, pH 3.5 to pH4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent, pH 2. 0 to pH 4.0, dissociation temperature 65 ° C.) “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211” (p -Toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C.), “ NACURE 5414 "(dodecylbenzenesulfonic acid dissociation, key Ren solvent, dissociation temperature 120 ° C.), “NACURE 5528” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C.), “NACURE 5925” (dodecylbenzenesulfonic acid dissociation, pH 7.0) PH 7.5 or less, dissociation temperature 130 ° C., “NACURE 1323” (disinyl naphthalene sulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene sulfonic acid Dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C.), “NACURE1557” (dinonylnaphthalenesulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “ NA CUREX 49-110 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.),“ NACURE 3525 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonyl naphthalene disulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE 3327” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “NACURE4167” (phosphoric acid dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, dissociation temperature 80 ), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0, dissociation temperature) 110 ° C.).

These thermal latent catalysts may be used alone or in combination of two or more.
Here, the compounding amount of the catalyst is at least one amount selected from the above guanamine compound (for example, a compound represented by the general formula (A)) and a melamine compound (for example, a compound represented by the general formula (B)) (application). The solid content concentration when the fluororesin particles or the fluorinated alkyl group-containing copolymer in the liquid is removed) is preferably in the range of 0.1% by mass to 50% by mass, particularly 10% by mass. More than 30 mass% is desirable. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that this is because a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

-Formation of surface protective layer-
The surface protective layer 5 having the above configuration includes fluorine resin particles and a fluorinated alkyl group-containing copolymer, and desirably a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (the general formula (B And a coating solution for forming a surface protective layer containing at least one selected from the compound represented by (1) and the specific charge transporting material. This surface protective layer forming coating solution is added with any other component of the surface protective layer 5 as necessary.

  The coating solution for forming the surface protective layer is prepared in the absence of a solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane. You may carry out using solvents, such as a kind. Such solvents are used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  The amount of the solvent is arbitrarily set, but if it is too small, a guanamine compound (for example, a compound represented by the general formula (A)) and a melamine compound (for example, a compound represented by the general formula (B)) are likely to precipitate. 0.5 parts by mass or more and 30 parts by mass with respect to 1 part by mass of at least one selected from a compound (for example, a compound represented by general formula (A)) and a melamine compound (for example, a compound represented by general formula (B)) Hereinafter, it is desirably used in an amount of 1 to 20 parts by mass.

  In addition, when the coating liquid is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C. for 10 minutes to 100 Heating may be performed for a period of time or less, preferably 1 hour or more and 50 hours or less. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it is easy to obtain a film with few coating film defects and little variation in film thickness.

  Then, a coating solution for forming the surface protective layer is usually applied on the charge transport layer 3 such as blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. After applying by this method, the surface protective layer 5 is obtained by heating and curing, for example, at a temperature of 100 ° C. or higher and 170 ° C. or lower as necessary.

  The film thickness of the surface protective layer 5 is desirably 1 μm or more and 15 μm or less, and more desirably 3 μm or more and 10 μm or less. If the thickness of the surface protective layer 5 is 1 μm or more, it is easy to achieve a long life, and if it is 15 μm or less, it is easy to achieve good electrical characteristics.

<Conductive substrate>
Examples of the conductive substrate 4 include a metal plate, a metal drum, and a metal belt formed using a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum. Alternatively, a paper, a plastic film, a belt, or the like on which a conductive compound such as a conductive polymer or indium oxide, or a metal or alloy such as aluminum, palladium, or gold is applied, vapor-deposited, or laminated can be given. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photosensitive member 7A is used in a laser printer, the surface of the conductive substrate 4 has a center line average roughness Ra of 0.04 μm or more to prevent interference fringes generated when laser light is irradiated. It is desirable to roughen the surface to 5 μm or less. If Ra is less than 0.04 μm, it becomes close to a mirror surface, so that the effect of preventing interference tends to be insufficient. If Ra exceeds 0.5 μm, the image quality tends to be rough even if a film is formed. When non-interfering light is used for the light source, it is not particularly necessary to roughen the interference fringes to prevent the occurrence of defects due to irregularities on the surface of the conductive substrate 4, which is suitable for longer life.

As a roughening method, wet grinding is performed by suspending an abrasive in water and spraying the surface of the conductive substrate 4, or the conductive substrate 4 is pressed against a rotating grindstone and continuously ground. Centerless grinding, anodizing treatment, etc. are preferable.
As another roughening method, the conductive substrate 4 is formed by dispersing conductive or semiconductive powder in the resin without roughening the surface of the conductive substrate 4. A method of forming a layer on the surface of the support and roughening with particles dispersed in the layer is also preferably used.

Here, the roughening treatment by anodic oxidation is to form an oxide film on the aluminum surface by anodizing in an electrolytic solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the anodic oxide film are sealed with pressurized water vapor or boiling water (a metal salt such as nickel may be added) by volume expansion due to a hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. It is desirable.
The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less. When this film thickness is less than 0.3 μm, the barrier property against implantation tends to be poor and the effect tends to be insufficient. On the other hand, if it exceeds 15 μm, the residual potential tends to increase due to repeated use.

Further, the conductive substrate 4 may be subjected to treatment with an acidic aqueous solution or boehmite treatment.
Examples of the treatment with the acidic aqueous solution include a treatment with an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid. The treatment with an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0.00%. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is preferably 42 ° C. or more and 48 ° C. or less, but by keeping the treatment temperature high, a thicker film can be formed faster than when the treatment temperature is lower than the range. The film thickness is preferably from 0.3 μm to 15 μm. If it is less than 0.3 μm, the barrier property against injection tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  The boehmite treatment is performed by immersing in pure water at 90 ° C. or more and 100 ° C. or less for 5 minutes or more and 60 minutes or less, or by contacting with heated steam at 90 ° C. or more and 120 ° C. or less for 5 minutes or more and 60 minutes or less. The film thickness is preferably 0.1 μm or more and 5 μm or less. This is further anodized using an electrolyte solution with lower film solubility than other types such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Processing may be performed.

<Underlayer>
The undercoat layer 1 is configured by containing inorganic particles in a binder resin, for example.
As the inorganic particles, those having a powder resistance (volume resistivity) of 10 ² Ω · cm to 10 ¹¹ Ω · cm are desirably used. This is because the undercoat layer 1 needs to obtain an appropriate resistance for leak resistance and carrier block property acquisition. In addition, if the resistance value of the inorganic particles is lower than the lower limit of the above range, sufficient leakage resistance cannot be obtained, and if it is higher than the upper limit of this range, there is a concern that the residual potential is increased.
Among these, inorganic particles (conductive metal oxide) such as tin oxide, titanium oxide, zinc oxide, and zirconium oxide are preferably used as the inorganic particles having the above resistance value, and zinc oxide is particularly preferably used.

The inorganic particles may be subjected to a surface treatment, or may be used as a mixture of two or more types such as those having different surface treatments or particles having different particle diameters.
The volume average particle size of the inorganic particles is desirably in the range of 50 nm to 2000 nm (preferably 60 to 1000). Also, as the inorganic particles, those having a specific surface area of 10 m ² / g or more by BET method are preferably used It is done. Those having a specific surface area value of less than 10 m ² / g tend to cause a decrease in chargeability and tend to make it difficult to obtain good electrophotographic characteristics.
Furthermore, by containing an acceptor compound together with the inorganic particles, an undercoat layer having excellent long-term electrical characteristics and excellent carrier blocking properties can be obtained.

  As the acceptor compound, any compound can be used as long as the desired characteristics are obtained. However, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, Fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, and 2,5 Oxadiazole compounds such as -bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, xanthone compounds, Desirable are electron transport materials such as thiophene compounds, diphenoquinone compounds such as 3,3 ′, 5,5′tetra-t-butyldiphenoquinone, Compounds having an anthraquinone structure are preferable. Furthermore, acceptor compounds having an anthraquinone structure such as hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, and the like are desirably used, and specific examples include anthraquinone, alizarin, quinizarin, anthralfin, and purpurin.

The content of these acceptor compounds may be arbitrarily set as long as desired characteristics are obtained, but is desirably 0.01% by mass or more and 20% by mass or less with respect to the inorganic particles. Furthermore, 0.05 mass% or more and 10 mass% or less are desirable from a viewpoint of preventing charge accumulation and preventing aggregation of inorganic particles. Aggregation of the inorganic particles tends to cause variations in the formation of the conductive path, which not only tends to cause deterioration in sustainability such as an increase in residual potential during repeated use, but also tends to cause image quality defects such as black spots.
The acceptor compound may be added only when the undercoat layer is applied, or may be previously attached to the surface of the inorganic particles. Examples of the method for imparting the acceptor compound to the surface of the inorganic particles include a dry method or a wet method.

  When surface treatment is performed by a dry method, dispersion is achieved by dropping an acceptor compound dissolved in an organic solvent directly or with dry air or nitrogen gas while stirring the inorganic particles with a mixer having a large shearing force. Is processed without any occurrence. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. When spraying at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before stirring without causing variation, and the acceptor compound is locally concentrated, which makes it difficult to perform the treatment without variation. After addition or spraying, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

  As a wet method, the inorganic particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., added with an acceptor compound, stirred or dispersed, and then the solvent is removed without causing variations. It is processed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, the water containing inorganic particles is also removed before adding the surface treatment agent. For example, a method of removing with stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropic distillation with the solvent. It may be used.

In addition, the inorganic particles may be subjected to a surface treatment before the acceptor compound is provided. The surface treatment agent is not particularly limited as long as it has desired characteristics and is selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, silane coupling agents are desirably used because they provide good electrophotographic properties. Further, a silane coupling agent having an amino group is desirably used because it gives the undercoat layer 1 good blocking properties.
Any silane coupling agent having an amino group may be used as long as the desired electrophotographic photoreceptor characteristics can be obtained. Specific examples include γ-aminopropyltriethoxysilane, N-β. -(Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane However, it is not limited to these.

Two or more silane coupling agents may be used in combination. Examples of silane coupling agents that may be used in combination with the silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyl Trimethoxysilane, etc. The present invention is not limited.
Any surface treatment method using these surface treatment agents may be used as long as it is a known method, but it is desirable to use a dry method or a wet method. Moreover, you may perform surface treatment by acceptor provision and a coupling agent etc. together.
The amount of the silane coupling agent with respect to the inorganic particles in the undercoat layer 1 is arbitrarily set as long as the desired electrophotographic characteristics can be obtained. It is desirable that the content is not less than 10% by mass and not more than 10% by mass.

  As the binder resin contained in the undercoat layer 1, any known resin can be used as long as it can form a good film and can obtain desired characteristics. For example, polyvinyl butyral Acetal resin, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin , Silicone resins, silicone-alkyd resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins and other known polymer resin compounds, charge transporting resins having a charge transporting group, and conductive resins such as polyaniline, etc. Is used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferable. When these are used in combination of two or more, the mixing ratio is set as necessary.

  In the coating solution for forming the undercoat layer, the ratio of the inorganic particles having the acceptor compound (metal oxide having the acceptor property) and the binder resin, or the inorganic particles and the binder resin to the surface is as desired. It is arbitrarily set as long as the photoreceptor characteristics can be obtained.

  Various additives may be used for the undercoat layer 1 in order to improve electrical characteristics, environmental stability, and image quality. As additives, known materials such as polycyclic condensation type, azo type electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, and the like are used. It is done. The silane coupling agent is used for the surface treatment of inorganic particles as described above, but may be further added to the coating solution for forming the undercoat layer as an additive.

Specific examples of the silane coupling agent as an additive include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β Examples include-(aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane.
Examples of zirconium chelate compounds include zirconium butoxide, ethyl zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, octanoic acid. Zirconium, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.
Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.
These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds.

Solvents for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. Optionally selected. Specific examples of the solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, and acetic acid. Usual organic solvents such as n-butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene are used.
Moreover, you may use these solvents individually or in mixture of 2 or more types. When mixing, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

As a dispersion method of the inorganic particles when preparing the coating liquid for forming the undercoat layer, known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker are used.
Furthermore, as a coating method used when providing the undercoat layer 1, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. Is used.
The undercoat layer 1 is formed on the conductive substrate using the undercoat layer-forming coating solution thus obtained.

The undercoat layer 1 preferably has a Vickers hardness of 35 or more.
Furthermore, the undercoat layer 1 is set to any thickness as long as desired characteristics can be obtained. The thickness is preferably 15 μm or more, and more preferably 15 μm or more and 50 μm or less.
When the thickness of the undercoat layer 1 is less than 15 μm, it is difficult to obtain sufficient leakage resistance, and when it is 50 μm or more, a residual potential tends to remain when used for a long period of time, which tends to cause an abnormal image density. There are drawbacks.

Further, the surface roughness (ten-point average roughness) of the undercoat layer 1 is from 1/4 n (n is the refractive index of the upper layer) to 1/2 λ of the exposure laser wavelength λ used to prevent moire images. Adjusted to
In order to adjust the surface roughness, particles such as resin may be added to the undercoat layer. As the resin particles, silicone resin particles, cross-linked polymethyl methacrylate resin particles, and the like are used.

  Here, the undercoat layer 1 contains a binder resin and a conductive metal oxide, and has a light transmittance of 40% or less (desirably 10% or more and 35% or less, more desirably) for light having a wavelength of 950 nm at a thickness of 20 μm. 15% or more and 30% or less) is desirable. It is necessary to maintain stable high image quality in an electrophotographic photosensitive member aimed at extending the life. Similar characteristics are also required when a crosslinkable outermost surface layer (protective layer) is used. When a crosslinkable outermost layer (surface protective layer) is used, an acid catalyst is often used for curing, and the greater the amount relative to the solid content in the outermost surface layer (surface protective layer), the higher the film strength. As a result, the printing durability can be improved, and the service life can be extended.

  On the other hand, the residual catalyst in the bulk becomes a charge trap site, so that the light fatigue resistance is lowered, and this causes image density unevenness due to light exposure during maintenance. This light resistance (light fatigue resistance) is improved to a level where there is no problem in practical use by optimizing the amount of the material (especially charge transport material, acid catalyst), but a bright environment such as a normal office, for example, It is not sufficient for high-intensity and long-time exposure, such as when irradiating at a showroom or when observing foreign matter adhering to the surface of an electrophotographic photoreceptor. It is necessary to increase the curing catalyst and increase the film strength, but in that case, the light resistance may not be sufficient. Therefore, by using the undercoat layer 1 having the predetermined light transmittance (that is, the light transmittance is low), the undercoat layer 1 absorbs the light incident on the electrophotographic photosensitive member, whereby the light having a high intensity. It is excellent in light resistance against light, and an image can be obtained stably over a long period of time. That is, since the reflected light from the surface of the conductive substrate is reduced, light resistance (light fatigue resistance) is obtained against light exposure for a long time with high brightness, and the amount of curing catalyst is increased, for example, the outermost surface layer (surface Even if the strength of the protective layer is increased and the printing durability is improved, a longer life can be realized.

The light transmittance of the undercoat layer 1 is measured as follows. The undercoat layer-forming coating solution is applied on a glass plate so that the thickness after drying is 20 μm, and after drying, the light transmittance of the film at a wavelength of 950 nm is measured using a spectrophotometer. For the light transmittance by the photometer, an apparatus name “Spectrophotometer (U-2000)” manufactured by Hitachi, Ltd. is used as a spectrophotometer.
The light transmittance of the undercoat layer 1 is controlled by adjusting the dispersion time at the time of dispersion using the roll mill, ball mill, vibration ball mill, attritor, sand mill, colloid mill, paint shaker or the like. The dispersion time is not particularly limited, but any time from 5 minutes to 1000 hours is desirable, and 30 minutes to 10 hours is more desirable. When the dispersion time is increased, the light transmittance tends to decrease.

Further, the surface of the undercoat layer 1 may be polished in order to adjust the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.
The undercoat layer 1 can be obtained by drying the above-described undercoat layer forming coating solution applied on the conductive substrate 4. Usually, drying is performed at a temperature at which the solvent evaporates to form a film.

<Charge generation layer>
The charge generation layer 2 is a layer containing a charge generation material and a binder resin.
Examples of the charge generating material include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, phthalocyanine pigments, zinc oxide, and trigonal selenium. Among these, metal and metal-free phthalocyanine pigments are desirable for near-infrared laser exposure. In particular, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, and the like. Chlorogallium phthalocyanine disclosed in JP-A-5-98181, dichlorotin phthalocyanine disclosed in JP-A-5-140472, JP-A-5-140473, etc., JP-A-4-189873, More preferred is titanyl phthalocyanine disclosed in Kaihei 5-43823. For near-ultraviolet laser exposure, condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, and trigonal selenium are more desirable. As the charge generation material, an inorganic pigment is desirable when a light source with an exposure wavelength of 380 nm to 500 nm is used, and a metal and a metal-free phthalocyanine pigment are desirable when a light source with an exposure wavelength of 700 nm or less and 800 nm is used.

  As the charge generation material, it is desirable to use a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm in a spectral absorption spectrum in a wavelength range of 600 nm to 900 nm. This hydroxygallium phthalocyanine pigment is different from the conventional V-type hydroxygallium phthalocyanine pigment, and is desirable because it provides better dispersibility. Thus, by shifting the maximum peak wavelength of the spectral absorption spectrum to a shorter wavelength side than the conventional V-type hydroxygallium phthalocyanine pigment, it becomes a fine hydroxygallium phthalocyanine pigment in which the crystal arrangement of the pigment particles is controlled. When used as a material for a photoconductor, excellent dispersibility and sufficient sensitivity, chargeability, and dark decay characteristics can be obtained.

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, more desirably 0.01 μm or more and 0.15 μm or less, while the BET specific surface area is desirably 45 m ² / g or more. 50 m ² / g or more is more desirable, and 55 m ² / g or more and 120 m ² / g or less is particularly desirable. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). Moreover, it is the value measured by the nitrogen substitution method using the BET-type specific surface area measuring device (Shimadzu Corporation make: Flow soap II2300).
When the average particle diameter is larger than 0.20 μm, or when the specific surface area value is less than 45 m ² / g, the pigment particles are coarsened or aggregates of the pigment particles are formed, and the electrophotographic photosensitive member When used as a material, there is a tendency that defects are likely to occur in characteristics such as dispersibility, sensitivity, chargeability, and dark decay characteristics, thereby tending to cause image quality defects.

The maximum particle diameter (maximum primary particle diameter) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and more desirably 0.3 μm or less. is there. When the maximum particle size exceeds the above range, minute black spots tend to occur.
Furthermore, from the viewpoint of more reliably suppressing density unevenness caused by exposure of the photoreceptor to a fluorescent lamp or the like, the hydroxygallium phthalocyanine pigment has an average particle size of 0.2 μm or less and a maximum particle size of 1.2 μm. The specific surface area value is preferably 45 m ² / g or more.

In addition, the hydroxygallium phthalocyanine pigment described above has Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, and 16.5 in an X-ray diffraction spectrum using CuKα characteristic X-rays. It is desirable to have diffraction peaks at 3 °, 18.6 °, 25.1 ° and 28.3 °.
The hydroxygallium phthalocyanine pigment preferably has a thermal weight reduction rate of 2.0% or more and 4.0% or less when heated from 25 ° C. to 400 ° C., and preferably 2.5% or more and 3.8%. % Or less is more desirable. The thermal weight reduction rate is measured by a thermobalance or the like. When the thermal weight reduction rate exceeds 4.0%, the impurities contained in the hydroxygallium phthalocyanine pigment affect the electrophotographic photosensitive member, and the sensitivity characteristics, potential stability during repeated use, and image quality decrease. Tend to occur. Further, if it is less than 2.0%, the sensitivity tends to be lowered. This is considered due to the fact that the hydroxygallium phthalocyanine pigment exhibits a sensitizing action by interaction with a solvent molecule contained in a small amount in the crystal.

When the above-described hydroxygallium phthalocyanine pigment is used as a charge generation material for an electrophotographic photoreceptor, the optimum sensitivity and excellent photoelectric characteristics of the photoreceptor can be obtained, and the binder resin contained in the photosensitive layer can be obtained. Since it has excellent dispersibility, it is particularly effective in that it has excellent image quality characteristics.
Here, it has been known that by defining the average particle diameter and the BET specific surface area of the hydroxygallium phthalocyanine pigment, it is possible to suppress the occurrence of initial fogging and black spots, but the problem of fogging and black spots occurring due to long-term use. was there. On the other hand, by combining a predetermined outermost layer (a protective layer made of a crosslinked film using at least one selected from a guanamine compound and a melamine compound and a specific charge transport material) described later, Generation of fog and black spots due to long-term use, which has been a problem with the combination of the layer and the charge generation layer, can be suppressed. This is presumably because film wear and chargeability degradation caused by long-term use are suppressed by using the protective layer. In addition, it is possible to suppress fogging and black spots that have been generated in the conventional photoconductors even for thinning of the charge transport layer, which is effective in improving electrical characteristics (reducing residual potential).

The binder resin used for the charge generation layer 2 is selected from a wide range of insulating resins, and selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Also good. Desirable binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic divalent carboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamides. Resins, acrylic resins, polyacrylamide resins, polyvinyl pyridine resins, cellulose resins, urethane resins, epoxy resins, caseins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, and the like. These binder resins are used singly or in combination of two or more. The blending ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by mass ratio. Here, “insulating” means here that “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.
The charge generation layer 2 is formed using a coating liquid in which a charge generation material and a binder resin are dispersed in a predetermined solvent.

Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These may be used alone or in admixture of two or more.
In addition, as a method for dispersing the charge generating material and the binder resin in the solvent, usual methods such as a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method can be used. By these dispersion methods, changes in the crystal form of the charge generation material due to dispersion are prevented. Further, at the time of dispersion, it is effective that the average particle size of the charge generating material is 0.5 μm or less, desirably 0.3 μm or less, and more desirably 0.15 μm or less.

Further, when forming the charge generation layer 2, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. .
The film thickness of the charge generation layer 2 obtained in this way is desirably 0.1 μm or more and 5.0 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

<Charge transport layer>
The charge transport layer 3 is formed containing a charge transport material and a binder resin, or containing a polymer charge transport material.
Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore-transporting compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are desirable.

In Structural Formula (a-1), R ⁸ represents a hydrogen atom or a methyl group. n represents 1 or 2. Ar ⁶ and Ar ⁷ are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ⁹ ) ═C (R ¹⁰ ) (R ¹¹ ), or —C ₆ H ₄ —CH═CH—. CH = C (R ¹² ) (R ¹³ ) is represented, and R ^{9 to} R ¹³ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituent include a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

In Structural Formula (a-2), R ¹⁴ and R ^{14 ′} may be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy having 1 to 5 carbon atoms. Group. R ¹⁵ , R ^{15 ′} , R ¹⁶ , and R ^{16 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. , an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl ^{group, -C (R 17) = C} (R 18) (R 19), or -CH = CH-CH = C (R ²⁰ ) (R ²¹ ), wherein R ^{17 to} R ²¹ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m and n each independently represent an integer of 0 or more and 2 or less.

Here, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH ═C (R ¹² ) (R ¹³ ) ”and a benzidine derivative having“ —CH═CH—CH═C (R ²⁰ ) (R ²¹ ) ”have charge mobility, protective layer and It is excellent and desirable from the standpoints of adhesiveness and afterimage (hereinafter sometimes referred to as “ghost”) caused by the history of the previous image remaining.

  The binder resin used for the charge transport layer 3 is polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer. , Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly- N-vinyl carbazole, polysilane, etc. are mentioned. Further, polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 may be used. These binder resins are used singly or in combination of two or more. The blending ratio of the charge transport material and the binder resin is desirably 10: 1 to 1: 5 by mass ratio.

In particular, the binder resin is not particularly limited, but at least one of a polycarbonate resin having a viscosity average molecular weight of 50,000 to 80,000 and a polyarylate resin having a viscosity average molecular weight of 50,000 to 80,000 can be easily obtained. desirable.
In addition, a polymer charge transport material may be used as the charge transport material. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293, JP-A-8-208820 and the like have a higher charge transportability than other types, and are particularly desirable. is there. The polymer charge transport material can be formed by itself, but may be formed by mixing with a binder resin.

The charge transport layer 3 is formed using a charge transport layer forming coating solution containing the above-described constituent materials. Solvents used in the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenation such as methylene chloride, chloroform and ethylene chloride. Ordinary organic solvents such as aliphatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether or linear ethers may be used alone or in combination of two or more. Moreover, a well-known method is used as a dispersion method of each said constituent material.
The coating method for applying the charge transport layer forming coating solution onto the charge generation layer 2 includes blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, A usual method such as a curtain coating method is used.
The film thickness of the charge transport layer 3 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

  In the above, an example of the function-separated type photosensitive layer included in the electrophotographic photoreceptor 7A shown in FIG. 1 has been described. For example, the single-layer type photosensitive layer 6 included in the electrophotographic photoreceptor 7C shown in FIG. The content of the charge generation material in the (charge generation / charge transport layer) is about 10% by mass to 85% by mass, preferably 20% by mass to 50% by mass. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less. The method for forming the single-layer photosensitive layer 6 (charge generation / charge transport layer) is the same as the method for forming the charge generation layer 2 and the charge transport layer 3. The film thickness of the single-layer type photosensitive layer (charge generation / charge transport layer) 6 is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

  In each of the layers constituting the photosensitive layer in the electrophotographic photoreceptors 7A, 7B, and 7C shown in FIGS. 1 to 3, ozone or oxidizing gas generated in the image forming apparatus, light, or heat is applied to the photoreceptor. For the purpose of preventing deterioration, additives such as an antioxidant, a light stabilizer and a heat stabilizer may be added to each layer constituting the photosensitive layer. For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine. Further, at least one kind of electron-accepting substance is contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of the electron acceptor used include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m- Examples thereof include dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid and phthalic acid. Among these, fluorenone compounds, quinone compounds and Cl-, CN-, NO 2 _- benzene derivatives having an electron attractive substituent are particularly preferable.

  Further, when the surface protective layer 5 in the electrophotographic photoreceptors 7A, 7B and 7C shown in FIGS. 1 to 3 is treated with an aqueous dispersion containing a fluorine-based resin as in the case of the blade member, further torque reduction can be achieved. This is desirable because it can improve transfer efficiency and transfer efficiency.

[Image forming apparatus / process cartridge]
FIG. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the embodiment. As shown in FIG. 4, the image forming apparatus 100 includes a process cartridge 300 including the electrophotographic photosensitive member 7, an exposure device 9, a transfer device 40, and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 is exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member 7 via the intermediate transfer member 50. The intermediate transfer member 50 is partly in contact with the electrophotographic photosensitive member 7.

  The process cartridge 300 in FIG. 4 integrally supports the electrophotographic photoreceptor 7, the charging device 8, the developing device 11, and the cleaning device 13 in a housing. The cleaning device 13 has a cleaning blade 131 (blade member), and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7.

-Charging means-
As the charging device 8, for example, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger is used. Further, a contact type charger using a conductive or semiconductive charging roller, charging brush, charging film, charging rubber blade, charging tube or the like is also used. In the present embodiment, it is desirable to use a non-contact type charging unit that performs charging without contacting the photoconductor from the viewpoint of wear resistance and charging capability at high speed.
Although not shown, a photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member 7 and reducing the relative temperature is provided around the electrophotographic photosensitive member 7 for the purpose of improving the stability of the image. Also good.

-Electrostatic latent image forming means-
As the exposure apparatus 9 serving as an electrostatic latent image forming unit, for example, an optical system device or the like that exposes light such as semiconductor laser light, LED light, and liquid crystal shutter light on the surface of the photoreceptor 7 in a desired image manner. Can be mentioned. The wavelength of the light source is in the spectral sensitivity region of the photoreceptor. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength in the vicinity of 400 nm to 450 nm as a blue laser may be used. For color image formation, a surface-emitting laser light source that outputs multi-beams is also effective.

-Development means-
As the developing device 11, for example, a general developing device that performs development by bringing a magnetic or non-magnetic one-component developer or a two-component developer into contact or non-contact may be used. The developing device is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching the one-component developer or the two-component developer to the photoreceptor 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are desirable.

-Transfer means-
As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member 50, a drum-like one is used in addition to the belt shape.

-Cleaning means-
For example, as illustrated in FIG. 5, the cleaning blade 131 includes a support member 131D (support portion) and a rubber member 131C. The rubber member 131C is a member that is brought into pressure contact with the surface of a photoreceptor (not shown), and may have a two-layer structure including an edge layer 131A and a base layer 131B. When the rubber member 131C has a two-layer structure, the base layer 131B is bonded to the main surface of one end portion (one end portion in the width direction) of the support member 131D by bonding or the like with the main surface facing each other.

  Hereinafter, a cleaning blade having a two-layer structure will be described. In the rubber member 131C, the edge layer 131A has a function of scraping off toner remaining on the surface of the photoconductor, and the base layer 131B has a function of adjusting the force with which the edge portion of the elastic rubber member 131C comes into contact with the photoconductor.

  The base layer 131B is a layer having a hardness lower than that of the edge layer 131A. As the base layer 131B, at 23 ° C., the type A durometer hardness (JISA hardness) is HsA58 or higher and HsA76 or lower (preferably HsA60 or higher and HsA75 or lower), and the rebound elastic modulus is 21% or higher and 40% (preferably, 25% or more and 35% or less) and a material having a permanent elongation of 3% or less (preferably 0.5% or more and 1.5% or less).

  The thickness of the edge layer 131A indicated by a in FIG. 5 is preferably 0.2 mm or more and 1.5 mm or less, and more preferably 0.5 mm or more and 1.0 mm or less. The thickness of the base layer 131B indicated by b in FIG. 5 is preferably 1.0 mm or greater and 3.0 mm or less, and more preferably 1.5 mm or greater and 2.5 mm or less. The thickness ratio (a: b) between the edge layer 131A and the base layer 131B is preferably 1:20 to 1: 2, and more preferably 1:10 to 1: 3.

  Specifically, the elastic material for forming the rubber member 131C is desirably made of polyurethane, for example. The polyurethane is not particularly limited as long as it is usually used for forming polyurethane. For example, a urethane prepolymer composed of a polyol such as a polyester polyol such as polyethylene adipate or polycaprolactone and an isocyanate such as diphenylmethane diisocyanate, and 1 A rubber member obtained from a crosslinking agent such as 1,4-butanediol, trimethylolpropane, ethylene glycol, or a mixture thereof is desirable from the viewpoint of excellent abrasion resistance and high mechanical strength. As the urethane prepolymer, for example, an NCO group content of 4% by mass to 10% by mass and a viscosity at 70 ° C. of 1000 mPa · s to 3000 mPa · s are desirable.

  When the rubber member 131C is manufactured from polyurethane, a polyurethane molding method that is generally used may be used, and examples thereof include the following methods. First, the crosslinking agent and the like are added to a prepolymer obtained by mixing the polyol subjected to the dehydration treatment and the isocyanate and reacting at a temperature of 100 ° C. or higher and 120 ° C. or lower for 30 minutes or longer and 90 minutes or shorter. The base layer 131B is formed by injecting into a mold of a pre-heated centrifugal molding machine and curing for 5 minutes to 15 minutes. After the curing reaction, the edge layer 131A is formed by injecting the edge layer material similarly pretreated onto the cured base layer and curing it for 30 minutes to 60 minutes. After the curing reaction, a cylindrical two-layer structure sheet having a thickness of 2 mm or more and 3 mm or less is obtained by taking out from the mold. This is cut into strips having a width of 5 mm to 30 mm and a length of 200 mm to 500 mm to obtain a rubber member 131C.

  The support member 131D is not particularly limited, and for example, a support member 131D that is integral with the housing of the cleaning device or a mounting bracket for attachment to the housing corresponds to the support member 131D. Examples of the mounting bracket include metal, plastic, ceramic, etc. In particular, an untreated steel plate, a steel plate subjected to a surface treatment such as zinc phosphate treatment or chromate treatment, and other plating treatments. A mounting bracket made of a steel plate or the like is desirable because it does not cause a change over time such as corrosion.

  The adhesion method between the rubber member 131C and the support member 131D is not particularly limited. For example, an adhesion method using an EVA-based, polyamide-based, polyurethane-based hot-melt adhesive, epoxy-based, or phenol-based adhesive is used. Among these bonding methods, it is desirable to use a hot melt bonding method.

  The pressure contact force of the cleaning blade 131 (rubber member 131C) to the photosensitive member is desirably 10 N / m or more and 80 N / m or less, more desirably 15 N / m or more and 60 N / m or less, and further desirably 20 N / m. It is 50 N / m or less. By setting the pressure contact force within the above range, the toner removing ability is improved and the local force on the surface of the photoreceptor is suppressed. As a result, local wear on the surface of the photoreceptor is suppressed, and a good image is easily obtained repeatedly over a long period of time.

  Further, an example is shown in which a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the photoreceptor 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are used. It may be used accordingly.

  In addition to the above-described devices, the image forming apparatus 100 may include, for example, a light neutralizing device that performs light neutralization on the photoconductor 7.

  FIG. 6 is a schematic sectional view showing an image forming apparatus according to another embodiment. As shown in FIG. 6, the image forming apparatus 120 is a tandem-type full-color image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

When the electrophotographic photosensitive member of this embodiment is used in a tandem type image forming apparatus, the electric characteristics of the four photosensitive members are stabilized, so that an image quality with excellent color balance can be obtained over a longer period.
Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing unit) includes a developer holding body having a magnetic material, and is a two-component developer containing a magnetic carrier and toner. It is desirable to develop an image. In this configuration, a clearer image quality can be obtained with a color image, and higher image quality and longer life can be achieved compared to the case of a one-component developer, particularly a non-magnetic one-component developer.

  In the image forming apparatus according to this embodiment, it is desirable that the process speed, that is, the moving speed of the outer peripheral surface of the electrophotographic photosensitive member is a high speed of 500 mm / s or more. Even when image formation is repeated by such a high-speed process, wear of the surface protective layer of the photoreceptor is suppressed, and an image with suppressed image flow can be obtained with high productivity.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following, “part” is based on mass unless otherwise specified.

100 parts by mass of zinc oxide (average particle size 70 nm: manufactured by Teica: specific surface area value 15 m ² / g) is stirred and mixed with 500 parts by mass of toluene, and silane coupling agent (KBM603: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.25 parts by mass. And stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide pigment.
100 parts by mass of the surface-treated zinc oxide was stirred and mixed with 500 parts by mass of tetrahydrofuran, a solution prepared by dissolving 1 part by mass of alizarin in 50 parts by mass of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 5 hours. Then, the zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain an alizarin imparted zinc oxide pigment.
60 parts by mass of this alizarin-added zinc oxide pigment, 13.5 parts by mass of hardener-blocked isocyanate Sumijoule 3175 (manufactured by Sumitomo Bayern Urethane) and 15 parts by mass of butyral resin BM-1 (manufactured by Sekisui Chemical) 85 parts by mass of methyl ethyl ketone 38 parts by mass of the solution dissolved in 25 parts by mass and methyl ethyl ketone 25 parts by mass were mixed for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion.

As a catalyst, 0.005 parts by mass of dioctyltin dilaurate and 40 parts by mass of silicone resin particle Tospearl 145 (manufactured by GE Toshiba Silicone) are added to the resulting dispersion as a catalyst, followed by drying and curing at 170 ° C. for 40 minutes. A forming coating solution was obtained.
This coating solution was dip-coated on an aluminum substrate having a diameter of 60 mm, a length of 357 mm, and a thickness of 1 mm by a dip coating method to obtain an undercoat layer having a thickness of 20 μm.

<Charge generation layer>
Next, chlorogallium having a strong diffraction peak at a Bragg angle (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 °, and 28.3 ° as a charge generation material. 1 part by weight of phthalocyanine crystals was added to 100 parts by weight of butyl acetate together with 1 part by weight of polyvinyl butyral resin (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.), and dispersed by treating with glass beads for 1 hour with a paint shaker. Thereafter, the obtained coating solution was dip-coated on the surface of the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.2 μm.

<Charge transport layer>
Furthermore, 2.1 parts by mass of the compound 1 represented by the following formula, 2.9 parts by mass of the polymer compound represented by the following structural formula 1 (viscosity average molecular weight: 39,000), 10 parts by mass of tetrahydrofuran and 5 parts by mass of toluene The coating solution obtained by dissolving in the solution was dip coated on the surface of the charge generation layer and dried by heating at 135 ° C. for 35 minutes to form a charge transport layer having a thickness of 24 μm.

<Surface protective layer>
10 parts of Lubron L-2 (manufactured by Daikin Industries) as tetrafluoroethylene resin particles and a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the following structural formula 2 (weight average molecular weight 50,000, l: (m = 1: 1, s = 1, n = 60) 0.5 parts and cyclopentanone 40 parts were sufficiently stirred and mixed to prepare a tetrafluoroethylene resin particle suspension.
Next, 65 parts of the compound represented by the chemical formula I-8, 30 parts of the compound represented by the chemical formula I-26, and 4 parts of benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.), respectively. In addition to 220 parts of cyclopentanone, after sufficiently dissolving and mixing, the tetrafluoroethylene resin particle suspension was added and mixed by stirring. Next, using a high-pressure homogenizer (YSNM-1500AR manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having a fine flow path, the dispersion treatment was repeated 20 times by increasing the pressure to 700 kgf / cm ² , and then dimethylpolysiloxane. 1 part of (Granol 450, Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry) were added to prepare a coating solution for forming a surface protective layer. The surface protection layer forming coating solution is applied onto the charge transport layer by a dip coating method and dried at 155 ° C. for 35 minutes to form a surface protection layer having a thickness of about 6 μm. It was set to 1.

[Photoreceptor 2]
In the formation of the surface protective layer of the photoreceptor 1, 10 parts to 5 parts of Lubron L-2 (manufactured by Daikin Industries) in the tetrafluoroethylene resin particle suspension and 0.5 parts of the fluorinated alkyl group-containing copolymer are used. Then, 0.25 parts from the part and 20 parts of cyclopentanone were changed and sufficiently stirred and mixed to prepare a tetrafluoroethylene resin particle suspension. Thereafter, the photoconductor obtained in the same manner as the photoconductor 1 was used as the photoconductor 2.

[Photoreceptor 3]
In the formation of the surface protective layer of the photoreceptor 1, 10 parts to 15 parts of Lubron L-2 (manufactured by Daikin Industries) in a tetrafluoroethylene resin particle suspension, and a fluoroalkyl group-containing copolymer 0.5 The amount of cyclopentanone was changed from 40 parts to 80 parts, and the mixture was thoroughly stirred and mixed to prepare a tetrafluoroethylene resin particle suspension. Thereafter, the photoconductor obtained in the same manner as the photoconductor 1 was used as the photoconductor 3.

[Photosensitive member 4]
In the formation of the surface protective layer of the photoreceptor 1, 10 parts to 20 parts of Lubron L-2 (manufactured by Daikin Industries) in a tetrafluoroethylene resin particle suspension and 0.5 parts of a fluorinated alkyl group-containing copolymer From 1.0 part to 1.0 part cyclopentanone was changed from 40 parts to 88 parts and mixed thoroughly with stirring to prepare a tetrafluoroethylene resin particle suspension. Thereafter, the photoconductor obtained in the same manner as the photoconductor 1 was used as the photoconductor 4.

[Photoreceptor 5]
In the formation of the surface protective layer of the photoreceptor 1, 10 parts to 30 parts of Lubron L-2 (manufactured by Daikin Industries) in a tetrafluoroethylene resin particle suspension and 0.5 parts of a fluorinated alkyl group-containing copolymer are used. From 1.5 parts to 1.5 parts, cyclopentanone was changed from 40 parts to 120 parts, and the mixture was sufficiently stirred and mixed to prepare a tetrafluoroethylene resin particle suspension. Thereafter, the photoconductor obtained in the same manner as the photoconductor 1 was designated as the photoconductor 5.

[Photoreceptor 6]
In the formation of the surface protective layer of the photoreceptor 1, it is obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 is changed to 75 parts and the compound represented by the chemical formula I-26 is changed to 20 parts. The obtained photoreceptor was designated as photoreceptor 6.

[Photoreceptor 7]
In the formation of the surface protective layer of the photoreceptor 1, it was obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 55 parts and the compound represented by the chemical formula I-26 was changed to 40 parts. This photoreceptor was designated as photoreceptor 7.

[Photoreceptor 8]
Photosensitivity obtained in the same manner as in Photoreceptor 1 except that the surface protective layer of Photoreceptor 1 was replaced with methylated melamine resin (B-2: Nicalac MW-30HM, manufactured by Sanwa Chemical Co., Ltd.). The photoconductor 8 was used as the photoconductor.

[Photoreceptor 9]
A photoreceptor obtained in the same manner as the photoreceptor 1 except that the surface protective layer of the photoreceptor 1 was changed to 68 parts of the compound represented by the chemical formula I-8 and 1 part of the benzoguanamine resin. It was set to 9.

[Photosensitive member 10]
In the formation of the surface protective layer of the photoconductor 8, a photoconductor obtained in the same manner as the photoconductor 8 except that the compound represented by the chemical formula I-8 was changed to a compound represented by the chemical formula I-16, It was set as the body 10.

[Photoreceptor 11]
A photoreceptor obtained in the same manner as the photoreceptor 8 except that the compound represented by the chemical formula I-26 was changed to the compound 2 represented by the following formula in the formation of the surface protective layer of the photoreceptor 8. It was set to 11.

[Photoreceptor 12]
In the formation of the surface protective layer of the photoreceptor 10, a photoreceptor obtained in the same manner as the photoreceptor 10, except that 67 parts of the compound represented by the chemical formula I-16 and 2 parts of the methylated melamine resin were changed, Photoconductor 12 was obtained.

[Photoreceptor 13]
A photoreceptor obtained in the same manner as the photoreceptor 12 except that the methylated melamine resin was changed to a benzoguanamine resin in the formation of the surface protective layer of the photoreceptor 12 was designated as the photoreceptor 13.

[Photoreceptor 14]
Photoreceptor obtained in the same manner as Photoreceptor 8 except that the surface protective layer of Photoreceptor 8 was changed to 54 parts of the compound represented by Formula I-8 and 15 parts of benzoguanamine resin as methylated melamine resin. Was used as a photoreceptor 14.

[Photoreceptor 15]
In the formation of the surface protective layer of the photoreceptor 1, it was obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 85 parts and the compound represented by the chemical formula I-26 was changed to 10 parts. This photoreceptor was designated as photoreceptor 15.

[Photosensitive member 16]
In the formation of the surface protective layer of the photoreceptor 1, it was obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 90 parts and the compound represented by the chemical formula I-26 was changed to 5 parts. The obtained photoreceptor was designated as photoreceptor 16.

[Photoreceptor 17]
In the formation of the surface protective layer of the photoreceptor 1, it was obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 50 parts and the compound represented by the chemical formula I-26 was changed to 45 parts. This photoreceptor was designated as photoreceptor 17.

[Photoreceptor 18]
In the formation of the surface protective layer of the photoreceptor 1, a photoreceptor obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 44 parts and the benzoguanamine resin was changed to 25 parts. It was set to 18.

[Photoreceptor 19]
In the formation of the charge transport layer of the photoreceptor 1, a photoreceptor obtained in the same manner as the photoreceptor 1 except that 2 parts by mass of the compound 3 and the compound 4 represented by the following formulas were used instead of the compound 1, It was set as the body 19.

[Photoreceptor 20]
In the formation of the surface protective layer of the photoreceptor 19, it was obtained in the same manner as the photoreceptor 19 except that 55 parts of the compound represented by the chemical formula I-8 and 40 parts of the compound represented by the chemical formula I-26 were changed. This photoreceptor was designated as photoreceptor 20.
[Photosensitive member 21]
It was produced in the same manner as the photoreceptor 1 until the charge transport layer was formed.
10 parts of Lubron L-2 (manufactured by Daikin Industries) as tetrafluoroethylene resin particles and a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the structural formula 2 (weight average molecular weight 50,000, l: (m = 1: 1, s = 1, n = 60) 0.5 parts and cyclopentanone 40 parts were sufficiently stirred and mixed to prepare a tetrafluoroethylene resin particle suspension.

  Next, the constituent materials shown below were dissolved in 5 parts by mass of isopropyl alcohol, 3 parts by mass of tetrahydrofuran, and 0.3 parts by mass of distilled water, 0.5 parts by mass of ion exchange resin (Amberlyst 15E) was added, and The hydrolysis was carried out for 24 hours by stirring.

-Constituent material-
Compound 5 having the following structure: 2 parts by mass Methyltrimethoxysilane: 2 parts by mass Tetramethoxysilane: 0.5 parts by mass Colloidal silica: 0.3 parts by mass

0.1 parts by mass of aluminum trisacetylacetonate (Al (aqaq) ₃ ), 3,5-di-t-butyl-4-hydroxytoluene (Liquid) obtained by filtering and separating the ion exchange resin from the hydrolyzed product BHT) After adding 0.4 parts by mass and sufficiently dissolving and mixing, after adding the tetrafluoroethylene resin particle suspension and stirring and mixing, a high-pressure homogenizer equipped with a through-type chamber having fine flow paths (Yoshida Kikai Kogyo Co., Ltd. YSNM-1500AR), after repeating the dispersion treatment by increasing the pressure up to 700 kgf / cm ² 20 times, 1 part of dimethylpolysiloxane (Granol 450, Kyoeisha Chemical), NACURE 5225 (King Industry) 0.1 part) was added to prepare a coating solution for forming a protective layer. This coating solution was applied onto the charge transport layer by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then cured by heat treatment at 170 ° C. for 1 hour to form a surface protective layer having a thickness of 7 μm. .
The obtained photoreceptor was designated as photoreceptor 21.

[Photosensitive member 22]
In the formation of the surface protective layer of the photoreceptor 1, it was obtained in the same manner as the photoreceptor 1 except that the compound represented by the chemical formula I-8 was changed to 94 parts and the compound represented by the chemical formula I-26 was changed to 0 parts. This photoreceptor was designated as photoreceptor 22.

[Photoreceptor 23]
It was produced in the same manner as the photoreceptor 1 until the charge transport layer was formed.
Next, 65 parts of the compound represented by the chemical formula I-8, 30 parts of the compound represented by the chemical formula I-26, and 4 parts of benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.), respectively. In addition to 240 parts of cyclopentanone, after sufficiently dissolving and mixing, 1 part of dimethylpolysiloxane (Granol 450, Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) are added to form a coating solution for forming a protective layer. Prepared. The surface-protecting layer-forming coating solution was applied onto the charge transport layer by a dip coating method and dried at 155 ° C. for 35 minutes to form a surface-sensitive layer having a thickness of about 6 μm.

[Photosensitive member 24]
It was produced in the same manner as the photoreceptor 1 until the charge transport layer was formed.
Next, 10 parts of Lubron L-2 (manufactured by Daikin Industries) as tetrafluoroethylene resin particles, a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the structural formula 2 (weight average molecular weight 50,000, l: m = 1: 1, s = 1, n = 60) and 40 parts of cyclopentanone were sufficiently stirred and mixed to prepare a tetrafluoroethylene resin particle suspension. Next, 70 parts of the compound represented by the chemical formula I-8 and 30 parts of the compound represented by the chemical formula I-26 were respectively added to 220 parts of cyclopentanone and sufficiently dissolved and mixed. After adding a suspension of fluoroethylene resin particles and stirring and mixing, the pressure is increased to 700 kgf / cm ² using a high-pressure homogenizer (YSNM-1500AR manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having fine flow paths. The dispersion treatment was repeated 20 times, and then 1 part of dimethylpolysiloxane (Granol 450, Kyoeisha Chemical) and 0.1 part of NACURE 5225 (manufactured by King Industries) were added to prepare a coating solution for forming a surface protective layer. . The surface-sensitive layer forming coating solution was applied onto the charge transport layer by a dip coating method and dried at 155 ° C. for 35 minutes to form a surface-sensitive layer having a film thickness of about 6 μm.

[Photoconductor 25]
In the formation of the surface protective layer of the photoreceptor 9, 59 parts of the compound represented by the chemical formula I-8, 40 parts of the compound represented by the compound 2 instead of the compound represented by the chemical formula I-26, and benzoguanamine resin A photoconductor obtained in the same manner as the photoconductor 9 except that it was changed to 1 part was designated as photoconductor 25.

[Photosensitive member 26]
In the formation of the surface protective layer of the photosensitive member 1, 40 parts of Lubron L-2 (manufactured by Daikin Industries), 2 parts of a fluorinated alkyl group-containing copolymer and 160 parts of cyclopentanone are mixed and mixed thoroughly. Thus, a tetrafluoroethylene resin particle suspension was prepared. Thereafter, the photoconductor obtained in the same manner as the photoconductor 1 was used as the photoconductor 26.

[Photoreceptor 27]
A photoreceptor obtained in the same manner as the photoreceptor 1 except that the surface protective layer was not formed on the photoreceptor 1 was designated as a photoreceptor 27.

[Photoreceptor 28]
It was produced in the same manner as the photoreceptor 1 until the charge transport layer was formed.
1.5 parts of a fluorine atom-containing polymer (trade name: GF-300, manufactured by Toagosei Co., Ltd.) as a dispersant was added to 1,1,2,2,3,3,4-heptafluorocyclopentane (product) Name: ZEOLORA H, manufactured by Nippon Zeon Co., Ltd.), dissolved in 150 parts of a fluorinated solvent, and then used as a lubricant, 30 parts of tetrafluoroethylene resin particles (trade name / Lublon L-2, manufactured by Daikin Industries, Ltd.) Was added to a high pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, USA) at a pressure of 600 kgf / cm ² (58.84 MPa) three times to uniformly disperse. This was filtered with a 1 μm PTFE membrane filter to prepare a lubricant dispersion. Thereafter, 70 parts of the hole transporting compound represented by the following formula (6) is added to the lubricant dispersion, followed by filtration with a PTFE prefilter (trade name: PF020, manufactured by Advantech Toyo Co., Ltd.) to form a surface protective layer. A coating solution was prepared.

The surface layer forming coating solution was applied on the charge transport layer by dip coating while circulating. After coating, the film is dried by heating at 50 ° C. for 10 minutes, and after heating and drying, the film is irradiated with an electron beam in a nitrogen atmosphere under conditions of an acceleration voltage of 150 KV and a dose of 20 Mrad (2 × 10 ⁵ Gy) to cure the resin. A photoreceptor obtained by forming a surface protective layer having a thickness of 5 μm was designated as a photoreceptor 28.

[Image formation test]
<Examples 1-15, 18-20, Reference Examples 16-17, 21-22, and Comparative Example 1-6>
An image formation test was performed using the photoreceptors 1 to 28. The experimental machine used was a copying machine modified from Fuji Xerox DocuCentre-II C7500 so that an image could be formed at 150 sheets / minute. In the test, a black and white mode was used, and a normal test (75 sheets / minute) and a high-speed test (150 sheets / minute) were performed as necessary. In the test, after forming an image of 100,000 sheets of A4 paper at an image density of 5% in an environment of high temperature and high humidity (28 ° C., 80% RH), electrical characteristics evaluation, resolution evaluation, and surface protection per 1000 rotations of the photoreceptor The wear amount (nm) of the layer was evaluated.

1. Evaluation of electrical characteristics First, as an evaluation of the electrical characteristics of the photoreceptor, the developing means is removed, a surface potential meter is installed, and the grid voltage of the scorotron (non-contact charging means) is set so that the photoreceptor surface potential is -700V. Adjusted. Next, the exposure light amount was set so that the exposure portion potential was −350V. After forming 100,000 images using this amount of exposure light, the exposed portion potential was measured again, and the difference from the initial value was expressed as ΔVL.
○: ΔVL <10
Δ: 10 ≦ ΔVL <15
×: 15 ≦ ΔVL

2. Evaluation of resolution (image flow) The grid voltage and exposure light amount of the scorotron were adjusted in the same manner as in the initial evaluation of the electrical characteristics of the photoconductor. Next, a 3pt character was printed, the character was enlarged and observed, and it was evaluated whether the character was disturbed or crushed.
○: Good as shown in FIG. 7A △: Partial disturbance or faint as shown in FIG. 7B (characters can be distinguished)
X: Characters are crushed as shown in FIG.

3. Amount of wear The amount of wear is measured by measuring the initial film thickness of the surface protective layer in advance during the image forming test, and measuring the difference between the initial film thickness and the film thickness after rotation of the photoconductor 1000. The amount of wear (nm) was calculated. The film thickness was measured with a permscope manufactured by Fischerscope.
○: Less than 2.5 nm Δ: 2.5 nm or more, less than 5 nm ×: 5 nm or more

4). High-speed test In the high-speed test, the above-described electrical property evaluation was performed at a double speed of normal speed (high-speed mode: 640 mm / s). In the evaluation method, as in the normal test, the grid voltage of the scorotron (non-contact type charging means) is adjusted so that the photoreceptor surface potential becomes −700 V in the high-speed mode, and then the exposed portion potential becomes −350 V. The amount of exposure light was set. After forming 100,000 images in the high-speed mode using this exposure light quantity, the exposed portion potential was measured again, and the difference from the initial value was expressed by ΔVL.
○: ΔVL <10
Δ: 10 ≦ ΔVL <20
×: 20 ≦ ΔVL

5. Evaluation Criteria for Comprehensive Judgment Based on the evaluation results of electrical property evaluation, resolution evaluation, wear amount, and high-speed test, comprehensive evaluation was performed based on the following criteria.
○: Good (up to 2 △)
△: Slightly inferior, but no problem (up to 3 △)
×: Unusable (x is 1 or more)

<Example 23>
An image formation test was performed using the photoreceptor 1. The experimental machine used was a machine in which the scorotron of the copying machine used in Example 1 was replaced with a charging roll (contact type charging means). In the test, a black and white mode was used, and a normal test (75 sheets / minute) and a high-speed test (150 sheets / minute) were performed as necessary. In the test, after image formation of 100,000 sheets of A4 paper at an image density of 5% in a high temperature and high humidity (28 ° C., 80% RH) environment, as in Example 1, evaluation of electrical characteristics, resolution evaluation, and photosensitivity were performed. The amount of wear (nm) of the surface protective layer per 1000 revolutions of the body was evaluated.
The results are shown in Table 1.

  As shown in Table 1, in the example, compared with the comparative example, the toner remaining on the surface of the electrophotographic photosensitive member after transferring the toner image to the transfer medium is excellent and repeatable over a long period of time. It can be seen that an image is obtained.

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Charge generation layer, 3 Charge transport layer, 4 Conductive substrate, 5 Surface protective layer, 6 Single layer type photosensitive layer, 7, 7A, 7B, 7C Electrophotographic photoreceptor, 8 Charging device, 9 Exposure Device, 11 Developing device, 13 Cleaning device, 14 Lubricant, 18 Non-contact charger, 40 Transfer device, 50 Intermediate transfer member, 100, 110, 120 Image forming device, 131 Cleaning blade, 132 Fibrous member, 133 Fiber Shaped member, 300 process cartridge

Claims (7)

An outermost surface layer containing fluororesin particles and a fluorinated alkyl group-containing copolymer, and satisfying the following formula (1):
Charging means for charging the electrophotographic photoreceptor;
A latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
Cleaning means for removing the developer remaining on the surface of the electrophotographic photosensitive member;
Bei to give a,
The outermost surface layer of the electrophotographic photoreceptor is
At least one selected from guanamine compounds and melamine compounds;
At least one selected from a crosslinkable charge transport material having an alkoxy group and a structure derived from a crosslinkable charge transport material having an alkoxy group;
Further including
The total content of the guanamine compound and the melamine compound with respect to the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer is 0.1% by mass or more and 20% by mass or less. Yes,
Derived from the crosslinkable charge transport material having the alkoxy group and the crosslinkable charge transport material having the alkoxy group, based on the total solid content of the outermost surface layer excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer. An image forming apparatus having a total content of 10% to 40% by mass .
10 ≦ A × B ≦ 50 (1)
A: Total content [% by mass] of fluorine-based resin particles and fluorinated alkyl group-containing copolymer contained in the outermost surface layer
B: Abrasion amount of outermost layer when the electrophotographic photosensitive member is rotated 1000 [nm]   2. The image forming apparatus according to claim 1, wherein the total content of the fluorine-based resin particles and the fluorinated alkyl group-containing copolymer in the outermost surface layer of the electrophotographic photosensitive member is 21% by mass or less. The electrophotographic outermost layer of the photoreceptor, a crosslinkable charge transporting material having a water group, and at least one further including請 Motomeko selected from a structure derived from a crosslinkable charge transporting material having a hydroxyl group 1 Alternatively, the image forming apparatus according to claim 2.   The said fluorine-type resin particle contains at least 1 sort (s) chosen from the polymer of a tetrafluoroethylene and the copolymer of a tetrafluoroethylene and perfluoroalkoxyethylene in any one of Claims 1-3. The image forming apparatus described. The fluorinated alkyl group-containing copolymer is a fluorinated alkyl group-containing copolymer containing repeating units represented by the following structural formula A and the following structural formula B. The image forming apparatus according to any one of the above.

(In Structural Formula A and Structural Formula B, l, m and n are integers of 1 or more, p, q, r and s are 0 or an integer of 1 or more, t is an integer of 1 or more and 7 or less, R ¹ , R ² , R ³ and R ⁴ are a hydrogen atom or an alkyl group, X is an alkylene chain, halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond, Y is an alkylene chain, halogen-substituted Represents an alkylene chain, — (C _z H _2z-1 (OH)) — or a single bond, _z represents an integer of 1 or more, and Q represents —O— or —NH—.   The image forming apparatus according to claim 1, wherein the charging unit is a unit that charges the electrophotographic photosensitive member without contacting the electrophotographic photosensitive member.   The image forming apparatus according to any one of claims 1 to 6, wherein a moving speed of an outer peripheral surface of the electrophotographic photosensitive member is 500 mm / s or more.